Owing to the competitive advantages of cost reduction, system downsizing, and reliability enhancement, position sensorless control methods for permanent magnet synchronous machine drives have drawn increasing attention from academia to industrial applications. In this article, a survey of the major sensorless control techniques for a wide speed range from low to high speeds is presented. The different high frequency signal injection schemes, fundamental pulsewidth modulation excitation methods, and model-based sensorless control are displayed and compared, which is able to facilitate the sensorless control implementation.

Position Sensorless Permanent Magnet Synchronous Machine Drives—A Review

A new quasi-Z-source inverter called switched-inductor quasi-Z-source inverter was presented which employs a switched-inductor impedance network to couple power source and the invert main circuitCompared with the traditional quasi-Z-source inverter,the switched-inductor quasi-Z-source inverter increases the voltage conversion rations,has an obvious voltage boost ability,and for a given voltage conversion ration,a higher modulation index can be used to ensure a good output power qualityTheoretical analysis,the experimental and simulative results based on the simple boost control strategy and the third harmonic injection control strategy verify the superiority and rationality of the new quasi-Z-source inverter and demonstrate the features of the third harmonic injection control strategy

Switched-inductor Quasi-Z-source Inverter

High voltage gain DC-DC converter is a prime requirement for renewable applications, in particular for PV. Though numerous DC-DC converter is available for increasing the voltage gain, the passive elements requirement is higher which reduces the compactness, consequently, increases the cost of the system. To address this issue, a high gain DC-DC converter is reported recently. However, the number of passive elements is quite high which increases the size. To reduce the number of passive elements and maintain the same number of semiconductor devices, in this paper, a new switched inductor arrangement is proposed which is named as switched inductor double switch DC-DC converter (SL-DS-DC). Moreover, the proposed converter has a higher gain as compared to the recently reported converter. The proposed converter is analyzed in steady state and a comparative analysis is presented to prove the suitability. Finally, the proposed converter is validated experimentally.

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Switched Inductor Double Switch High Gain DC-DC Converter for Renewable Applications

This paper proposes the design and experimental investigation of fuzzy precompensated hybrid proportional-integral (PI) controller for a permanent magnet synchronous motor (PMSM)-driven standalone solar water pumping system. A conventional PI controller usually has fixed gains, which makes them quite sensitive to the parameter variations. In order to improve its performance, both during dynamic and steady-state conditions, the presented controller introduces a fuzzy logic controller, which processes the speed error. The speed along with the processed output is inputted to the PI controller for speed control of PMSM. This topology uses a solar photovoltaic (PV) array to convert the solar power into electrical power. The energy obtained is utilized to rotate the PMSM using a 3- φ voltage-source inverter. The PMSM is coupled to a pump, which performs the water pumping. An intermediate stage dc–dc converter is utilized to maximize the power output using an incremental conductance algorithm. A PV feed-forward term is incorporated to provide an accelerated performance. This topology is modeled and its response is manifested through simulation studies using MATLAB/Simulink under different atmospheric conditions. A hardware validation of it is also carried out using a digital signal processor controller (dSPACE DS-1004) on a developed laboratory prototype.

Implementation of PMSM Drive for a Solar Water Pumping System

Conventional model-based sensorless surface-mounted permanent magnet synchronous motor (SPMSM) drivers suffer deteriorated performance in transient-state operation such as accelerating during wide-speed range or encountering large load torque disturbance. In this article, an effective sensorless control solution is proposed to improve the robustness of sensorless SPMSM drivers in transient-state operation. Two extended state observers (ESOs) are utilized to estimate the αβ -axis back electromotive forces (EMFs). An adaptive bandwidth tuning scheme is proposed to online tune the parameters of the ESOs, with which the desired estimation performance of back EMFs can be achieved in wide-speed operation range. Additionally, the dynamic mechanical behavior of the sensorless control system during large load torque transient is investigated by using small-signal analysis, and then a corresponding speed estimation compensation scheme for the conventional quadrature phase-locked loop (QPLL) is developed, with which the capability of QPLL in tracking the rapidly changing speed can be significantly enhanced. Experiments on an SPMSM demonstrate the superior robustness of the proposed method to that of the conventional method in transient-state operation.

Robustness Improvement of Model-Based Sensorless SPMSM Drivers Based on an Adaptive Extended State Observer and an Enhanced Quadrature PLL

This paper proposes a sensorless speed-control method based on an innovative adaptive synchronous-frequency tracking-mode observer (AFTO) for surface permanent-magnet synchronous motor drives. The method uses the AFTO function, based on proportional resonance control, to track stator currents adaptively under variable-frequency scenarios. Then, an orthogonal phase-locked loop supports the estimation of rotor speed. The convergence of stator-current errors guarantees an estimation of the back electromotive force (back EMF) without the influence of harmonic components and the chattering problem. The resulting pure and smooth back EMF provides high-accuracy estimates of the rotor position and speed. Simulations and experimental results are given to provide further validation of the proposed rotor-position and speed estimation schemes under different speed scenarios. The improved control method also maintains high estimation accuracy for rotor speed and position at low speeds.

Adaptive Synchronous-Frequency Tracking-Mode Observer for the Sensorless Control of a Surface PMSM

A compact high step up dc–dc converter with continuous input current and lower device voltage stress is a prime requirement for renewable application. In this article, a high gain dc–dc converter is proposed, which combines the concept of switched inductor and switched capacitor along with a unique interconnection of input–output. This arrangement reduces capacitor voltage stress. The proposed converter has reduced conduction losses, reduced components count, and low voltage stress across the devices. Besides, the proposed converter has lower inductor current ripple, which is suitable for renewable integration. The operation and steady-state analysis of the converter are done in continuous current mode. For the proposed converter, voltage and current stress and the losses are calculated analytically. A comparative analysis is presented to prove the potential of the proposed converter. The dynamic analysis of the proposed converter is performed to regulate the output voltage. Finally, an experimental set up is designed to test the converter under both distinct power ratings and closed loop.

Switched-LC Based High Gain Converter With Lower Component Count

The essential features of a DC–DC converter for fuel cell vehicle are to ensure the higher voltage gain to meet out the higher DC link voltage demand, continuous input current to improve the life span of the fuel cell, presence of common grounding to avoid electromagnetic interference issue and lower voltage stress with reduced components. This paper presents a high voltage gain DC–DC converter by combining the switched capacitor and quasi switched boost network modules. The proposed high voltage gain converter provides the continuous input current, lower voltage stress, utilizes a fewer number of elements and common grounding feature. The operating characteristics, steady-state analysis both in continuous current mode (CCM) and discontinuous current mode (DCM), comparative analysis with contemporary converters are discussed. The theoretical claimed analysis is validated by the simulation and experimental study. The proposed converter is operated for 200 W output power rating and tested for providing the voltage gain in the range of 5–8 times the input voltage gain by varying the input voltage from 25 V–40 V. The efficiency of the proposed converter is also reported for different output power rating which is in the range 91.3%–93.7%.

A High Voltage Gain DC–DC Converter With Common Grounding for Fuel Cell Vehicle

A high voltage gain inverter is a prime requirement for high voltage power application. Z-source inverter has attracted the attention widely. A lot of efforts has been made to improve the voltage gain with better design. However, still, there is a gap to achieve higher voltage gain with the optimum number of components. In this brief, a quasi Z-source inverter is proposed to achieve higher voltage gain. The proposed inverter utilizes the active switched network along with switched inductor cell. The proposed inverter offers continuous input current and higher voltage gain. The operation and steady-state analysis are presented to derive the voltage gain. A comparative analysis is presented to describe the features of the proposed inverter. Finally, an experimental analysis is conducted to validate the feasibility of the proposed inverter.

An Ultra High Gain Quasi Z-Source Inverter Consisting Active Switched Network

An interesting feature of a Z-source inverter is to provide buck–boost ability in a single stage. However, this concept is most popular in the conventional inverters. In a few multilevel inverters (MLIs), Z-source is utilized to have higher gain along with retaining the advantages of an MLI such as better electromagnetic interference compatibility, low harmonic distortion, etc. However, the potential of the Z-source concept is not fully exploited in MLIs. To widen the feasibility of the Z-source concept in the MLI, a modular MLI is considered. In this article, a generalized switched inductor cell is selected as a Z-source network for integration, however, other Z-source networks such as quasi-boost network, quasi-switched boost network, two winding coupled inductor network, three winding coupled inductor network, etc., may be used in place of a switched inductor cell. The quantitative and qualitative analysis is done for the proposed converter in both the continuous current mode and discontinuous current mode. The analysis shows that a higher voltage gain can be achieved in the discontinuous current mode as compared to the continuous current mode. To control the proposed converter, two new modulation techniques are proposed, i.e., full shoot through and upper shoot through/lower shoot through. Finally, the proposed converter is validated experimentally in both the modes and for different modulation techniques.

Yi Wang

Papers

Adaptive Synchronous-Frequency Tracking-Mode Observer for the Sensorless Control of a Surface PMSM

Switched-LC Based High Gain Converter With Lower Component Count

A High Voltage Gain DC–DC Converter With Common Grounding for Fuel Cell Vehicle

An Ultra High Gain Quasi Z-Source Inverter Consisting Active Switched Network

A Generalized Switched Inductor Cell Modular Multilevel Inverter